Composite extrusion with width adjustment

Abstract: An improved extrusion apparatus includes an adjustable deckle (30) and a flow channel (46) in the deckle (30) that makes possible extrusion of a composite stream, and in particular a side-by-side composite stream.

Description: This invention relates to an apparatus according to the introductory portion of claim 1 and to a method for coextruding a composite stream according to the introductory portion of claim 6. Forming a composite stream, in particular a side-by-side composite stream, is well known. Exemplary patents include U.S. Patent Nos. 4,348,346 to Thompson, 4,533,510 to Nissel, 4,731,004 to Wenz, Jr., 4,784,815 to Cloeren and Wernery, Jr., and 5,120,484 to Cloeren. Mechanically dividing a manifold using an adjustable block, is illustrated by the Nissel patent. Control of the degree of overlap or intermix along the joined edges of adjacent flow streams, and control of the position of the joined edges across the composite stream width have been described. Particularly described are the effect of the location selected for the convergence locus and the effect of the relative flow volumes on control of these properties. An extrusion apparatus having deckles controlling stream flow within the apparatus and defining the exit slot width and hence product width, is well known. The deckles may be internal, external, or an external/internal combination. The deckles may be precise or snug fitting blockage devices termed "deckle plugs". Illustrative patents include U.S. Patent Nos. 3,018,515 to Sneddon, 4,057,385 to Yazaki et al and 4,659,302 to Maejima et al, and UK Patent Application No. 2,114,050. However, there remains a need for an improved extrusion apparatus capable of composite extrusion and product width adjustment. Summary of the Invention It is accordingly an object of the present invention to provide an improved extrusion apparatus that provides for composite extrusion, in particular side-by-side extrusion. It is a further object to provide an extrusion apparatus that also provides for product width adjustment. It is an even further object to provide for product width adjustment, without affecting the degree of intermix along joined edges of laterally converged flow streams, or the width of a side stream in the product. It is a still further object to provide for product width adjustment and side stream width adjustment. These objects are achieved by an apparatus according to claim 1 and by a method according to claim 6. Additional objects, advantages and novel features of the present invention are set forth in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following description or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of instrumentalities and combinations particularly pointed out in the appended claims. Conveniently, the main body may include a feed inlet channel in fluid communication with the deckle channel. Advantageously, the deckle may include a divider portion disposed between the flow passageways. An end plate of the apparatus beneficially may include an inwardly projecting portion disposed in precision sliding fit within the deckle channel to provide for directed, streamlined flow. Preferably, the deckle includes a full width portion that extends through an end of the apparatus, and that is provided with the flow channel. Preferably, the full width portion is disposed at least partially within a transverse flow-providing manifold of the first flow passageway. Also provided is a novel process for extruding a composite stream. By the process, a first flow stream is passed through a first passageway, a second flow stream is passed through a passageway in an adjustable deckle disposed in the first passageway, and faces of the flow streams are joined to form a composite stream. Beneficially, the composite stream width may be changed by adjustment of the extent of the deckle, without affecting the degree of intermix along the joined edges of laterally converged streams, or the width of the second stream in the composite. Thus, the position of the joined edges across the composite stream width may be advantageously unaffected. In an appropriate application such as to mechanically provide for width control of the second flow stream of the laminate, a second flow passageway may be formed by cooperation of a channel in a first deckle member, and an end of a second deckle member adjustably disposed downstream thereof in the first passageway. In this case, a face of the first deckle member mechanically forms a movably disposed end of the first flow passageway, and a face of the separately adjustable, second deckle member mechanically forms a movably disposed end of the composite flow passageway. As a result, the first flow passageway width may be maintained constant while the second stream width and product width may be mechanically changed by adjustment of the extent of the second deckle member. Alternatively, the first stream width and the second stream width may be inversely changed relative to one another, by adjustment of the extent of the first deckle member, while the product width is maintained constant. In the drawing and detailed description of the invention that follow, there are shown and essentially described only preferred embodiments of this invention, simply by way of illustration of the best mode contemplated of carrying out this invention. As will be realized, this invention is capable of other and different embodiments, and its several details are capable of modification in various respects, all without departing from the invention. Accordingly, the drawing and the detailed description are to be regarded as illustrative in nature, and not as restrictive. Brief Description of the Drawing Reference is now made to the accompanying drawing, which forms a part of the specification of the present invention. Figure 1 is a view of a preferred embodiment of a right hand side of an extrusion apparatus in accordance with the present invention; Figures 2 and 3 are enlarged, cross-sectional views taken substantially along lines 2--2 and 3--3 of Figure 1, and including the upper die body; Figures 4-8 are partial views similar to Figure 1, illustrating alternative flow-contacting faces of the deckle; Figures 9 and 10 are partial views similar to Figure 1, illustrating deckles that lack a divider portion; Figure 11 is a partial perspective view showing further details of the deckle adjustment mechanism of the apparatus of Figure 1; and Figures 12-14 are partial views similar to Figure 1, illustrating deckle assemblies having a full width, upper portion or member. Detailed Description of the Invention The present invention is directed to a novel extrusion apparatus beneficially providing for side-by-side extrusion for the production of sheet and film product, particularly edge-laminated, polymeric product. Advantageously, the apparatus includes an adjustable deckle for control of the product width. In one embodiment, product width may be changed by adjustment of the deckle, without affecting the degree of intermix along the joined edges of laterally converged flow streams, and without affecting the relative position of joined faces of a composite. In another embodiment, product width may be changed by adjustment of the deckle, and side stream width may also be mechanically changed. Although reference is made in this description to polymeric materials especially thermoplastic materials such as synthetic resins, it will be appreciated than the invention has applicability to a variety of flowable materials. Also, although the description refers to forming a laterally disposed composite stream, it will be appreciated that prior to convergence, a stream may already comprise a multilayer structure. Referring to Figure 1, a right hand side of a preferred embodiment of an extrusion apparatus 10 in accordance with the present invention is shown, with the midline of the apparatus indicated by a dashed line. It will be understood that the opposite side of apparatus 10 may be a mirror image of that shown. With reference also to Figures 2 and 3, extrusion apparatus 10 includes a main body formed by body portions 11,12 and having a flow passageway 14, which provides for a main direction of flow indicated by arrows. The flow passageway includes in downstream order, a feed channel 16, a transverse flow-providing manifold 18 by which a flow stream is spread widthwise, a channel portion 20 commonly termed a preland channel, and a land channel 22 that extends to an exit orifice 24 suitably in the form of a slot formed by lips 26,28. Conveniently, with particular reference to Figures 2 and 3, the manifold has a generally non-circular, and in particular a generally rectangular, cross-section, and may be of substantially constant cross-sectional area from end to end. Alternatively, the manifold cross-section may be for instance, generally circular or tear drop-shaped. Referring particularly to Figure 1, adjustably disposed within flow passageway 14 is a deckle 30. Beneficially, the deckle has a end portion 32 with a flow-contacting face 34 that mechanically forms a movably disposed end of at least manifold 18 of flow passageway 14. Face 34 includes an upper, concavely radiused face, and a downstream, convexly radiused face 36. The adjustable deckle is illustrated as partially extended within the flow passageway. Advantageously, with particular reference again to Figures 2 and 3, deckle 30 is disposed in precision or snug fit within flow passageway 14 so as to serve as a flow blockage member or "plug". More particularly, the deckle is in precision sliding fit relationship with manifold 18, and may include a portion 38 that may extend to the exit orifice and that is likewise in precision sliding fit relationship with the flow passageway downstream of the manifold. Accordingly, the deckle may be beneficially provided with a shape that conforms to the surrounding flow passageway. The fit of deckle 30 is advantageously such that complete end closure of manifold 18 and channel 20 of flow passageway 14, except for necessary mechanical clearance, results. As may be understood, only portions of deckle 30 adjacent to flowing liquid, need a conforming shape to minimize or eliminate polymeric leakage. Also, the conforming shape will vary with the shape of the surrounding flow passageway. Thus, a deckle portion within a generally non-circular manifold will be generally non-circular in cross-section; whereas, a deckle portion within a generally circular manifold will be generally circular in cross-section. Beneficially, the deckle includes a full width portion. By "full width" is meant, for purposes of this description, having a transverse dimension substantially equal to or exceeding the maximum engagement of the particular member in the particular flow passageway. Generally speaking, and not by limitation, a maximum engagement length of a deckle disposed within a manifold will be about 25% of the manifold width. Accordingly, when retracted, a full width portion is not disposed in its entirety within the particular flow passageway, but rather extends through an end of the extrusion apparatus. Reference is hereby made to US-patent 5 505 609 and to corresponding EP 0 579 142 A1 which are directed to novel extrusion apparatus including full width deckles. Referring to Figures 1 to 3, deckle 30 advantageously includes a full width portion 42 disposed within the manifold, and a channel 46 in full width portion 42 provides a passageway for a separate flow stream. Conveniently, a feed inlet channel 48 in the main body of the apparatus is in fluid communication with flow channel 46. Suitably, channel 46 is generally transversely disposed and may extend to an end 50 of the deckle, which is operatively connected to an adjustment mechanism 52. As illustrated, a portion of the wall of manifold 18 may cooperate with a U-shaped recess in a deckle to form flow channel 46. Beneficially, an end plate 40 includes an advantageously concavely radiused, inwardly projecting portion 66 disposed in precision sliding fit within flow channel 46 to provide for directed, streamlined flow. The sliding fit permits the extent of the flow channel within main body 12 to be adjusted as necessary. Advantageously, generally transverse channel 46 communicates with a channel portion 54 in end 32 of the deckle so as to comprise a second flow passageway. In this case, deckle 30 includes a divider portion 56 disposed between the flow passageways and that provides for flow passageway convergence at a suitable locus 58. As may be understood from Figure 2, divider 56 is beneficially in precision sliding fit within flow passageway 14 and hence a plug. As earlier indicated, flow-contacting face 34 of divider 56 mechanically forms a movably disposed end of flow passageway 14. Suitably, divider 56 includes a second flow-contacting face formed by a linear face 60 and a downstream convexly radiused face 62; and faces 60,62 cooperate with a third flow-contacting face 64 of deckle 30 to define the width of channel portion 54. As can be understood from Figure 1, channel portion 54 is further defined by wall portions of flow passageway 14. As indicated, channel portion 54 may include a transverse flow-providing section and a channel portion similar to channel portion 20. Conveniently, radiused faces 36,62 of the divider terminate to form a tip 63, which is suitably disposed in channel portion 20. Downstream of tip 63, flow stream convergence occurs at locus 58 to provide for side-by-side, melt lamination. Face 64 of deckle portion 38 may extend to the exit slot. In such case, face 64 defines an end of the exit slot, and in combination with a like face at an opposite end of apparatus 10, defines the exit slot width and hence the product width. As illustrated, face 64 may be linear and generally perpendicular to the exit slot. As illustrated in Figures 4-8, the flow-contacting faces of the divider portion of the deckle may have a variety of shapes. In these Figures, like parts are designated with like numbers with respect to Figure 1. Thus, a downstream face may, for example, be linear (faces 136,162, Fig. 4; face 262, Fig. 5; face 436, Fig. 7), a rectilinear continuation of an upstream face (faces 236, 362 and 562 of Figs. 5, 6 and 8), or concavely radiused (face 536, Fig. 8). As also exemplified, a flow-contacting face of deckle portion 38 may have different shapes. For instance, with reference to Figure 7, an irregularly-shaped face 464 may cooperate with the opposing divider faces to provide a key-hole shape. The flow passageways may advantageously converge, as shown in Figure 1, upstream of and proximate to the exit orifice. Reference is hereby made to U.S. Patent No. 5,120,484 to Cloeren, previously cited, in which meaning of the term "proximate" and benefits of proximate convergence are discussed. Accordingly, it will be understood that "proximate" means from 0,32cm to about 7,62cm (from 1/8 to about 3") upstream of the exit orifice, but most typically about 2,54cm to 5,08cm (1 to 2 inches) upstream. However, selection of a convergence location may be driven by desire for overlap or intermix or blending at the joined edges or faces. Generally speaking, the closer a convergence locus is to the exit orifice, the sharper the seam definition; whereas, the further the locus is from the exit orifice, the less defined the seam becomes. In an appropriate application, convergence may be at or near the entry to channel portion 20. The width of a side stream in a laterally converged composite may be mechanically determined by the distance between divider tip 63 and flow-contacting face 64. However, the width may be altered by flow volume control, as a result of which the width of each joined stream within a given product width may be varied. For example, if flow passageway 14 has greater flow volume per unit width than the second flow passageway, then the side stream width in the composite will be reduced. As understood by one skilled in the art, the relative flow volumes through the passageways is related to the output of the respective extruders and flow restriction. As exemplified in Figures 9 and 10, the deckle channel (channels 46A, 46B) may comprise the second flow passageway. In this case, the deckle channel may open into manifold 18, with convergence of flow streams within the manifold. Side stream width is controlled by the relative flow volumes in this modification. Accordingly, the deckle may lack a divider portion disposed between flow passageways. The apparatus of these Figures otherwise correspond to apparatus 10 as indicated by the use of corresponding numbers to designate like parts. For sake of brevity therefore, details previously described are not repeated. With reference to Figures 1 and 11, in supporting connection with deckle 30 is an advantageous adjustment mechanism 52 for mechanically moving the deckle generally parallel to the exit slot and adjusting the extent of the deckle and of flow channel 46 within flow passageway 14. The adjustment mechanism includes a generally horizontal, support arm beneficially formed by generally parallel, spaced apart bars 70,72 each rigidly secured to main body 12 at one end, and connected at the other end by a member 73. Secured to an underside of bar 72 of the support arm is a toothed rack 74 in engagement with a pinion 76 provided on an end of a rotatable shaft 78 indirectly supported by the support arm. Directly Supported by the arm is an assembly arm 79 oriented generally perpendicular to the support arm and secured to end 50 of the deckle by a bolt 80. An upper portion 81 of the assembly arm is provided with a notched area to fit around bar 72 of the support arm so that an outwardly projecting portion 82 of the upper assembly arm rides on and along an upper surface of the support arm. In this way, the assembly arm is supported by and movable along the support arm, with sliding movement of the assembly arm toward or away from main body 12 and movement of deckle 30 and flow channel 46 being effected by rotation of the pinion in the corresponding direction. Attached to a face of the assembly arm are spaced apart bars 83,84, connected by a member 85. Rotatable shaft 78 is disposed between these spaced apart bars, and at the pinion end extends through an aperture in the assembly arm, and at an opposite end extends through an aperture in connecting member 85 and terminates in a hex head 86 for rotation of the pinion by suitable means such as a wrench. Advantageously fitted over the end of the shaft extending through connecting member 85 is a conveniently conventional ratchet clutch 87, which includes a lever 88 for effecting pawl/gear engagement/disengagement. Reference is made to US-patent 5 582 850 which describes an adjustment mechanism similar to mechanism 52. Figures 12-14 illustrate other useful deckles. The apparatus of these Figures correspond in many respects to apparatus 10 as indicated by the use of corresponding numbers to designate like parts. For sake of brevity therefore, details previously described are not repeated. As illustrated in Figure 12, it is sufficient for only an upper portion 90 of a deckle to be full width and to be within the manifold. In this case, the deckle may include an integral fin 91, which may beneficially extend to the exit slot thereby defining the exit slot width. To prevent leakage through end plate 40C around the full width portion of the deckle, a retainer member 92 and a sealing gasket 93 that cold forms under compression, are beneficially employed. Leakage-preventing members are omitted for simplification from the other Figures. As illustrated in the highly preferred embodiments of Figures 13 and 14, a deckle assembly may be used that includes a full width, upstream member 95 disposed beneficially within the manifold and including a flow channel 46D, and a separately adjustable, downstream member or members. Upstream member 95 advantageously includes a divider 56D having a face 34D that mechanically controls the width of at least manifold 18 of flow passageway 14. The upstream member including divider 56D, which suitably terminates in channel portion 20, is beneficially in precision sliding fit within the flow passageway and hence a plug. Separate adjustability of a downstream member advantageously permits mechanical width control of a side stream, and adjustment of the composite width, as earlier described. Beneficially, the deckle assembly components are located closely adjacent to, or in sliding fit contact with, one another. The additional deckle members may advantageously be plugs and be full width, and extend to the exit slot. Referring particularly to Figure 13, a full width, downstream deckle member 96 may be provided with a notch 97 in its outer end, and may have secured to the outer end, a member 98 having a threaded bore in alignment with the notch. A rotatable adjustment bolt 99 captured by the assembly arm, engages the threaded bore of member 98, for independent adjustability of deckle member 96. The width of channel portion 54D is defined in part by a flow-contacting face provided by ends 100,101 of deckle members 95,96, respectively. This flow-contacting face may be provided with a variety of suitable contours as well known in the art with respect to face 34D of the divider. Face 101 of deckle member 96, which advantageously is a plug and extends to the exit slot, defines the exit slot width and thus the composite width. As indicated, face 101 of deckle member 96 and face 34D of the divider of deckle member 95 are beneficially movable independently of each other. Referring to Figure 14, a full width, downstream deckle member 102 similar to deckle member 96 except with respect to length, is independently adjustable, with adjustability being provided by a rotatable adjustment bolt 103. Downstream of deckle member 102 is a deckle rod 104, which is advantageously disposed proximate to a transition wall 105 separating the preland and land channels. Independent adjustability of the deckle rod may be provided by a tightening mechanism 106, which makes frictional contact with a portion of the rod passing through the assembly arm. Channel portion 54E includes a flow-contacting face provided by ends 107,108,109 of deckle members 95,102,104, respectively. This face may, like the face provided in Figure 13 by deckle ends 95,96, be provided with a variety of suitable contours. As will be understood by one skilled in the art, end 109 of the deckle rod mechanically defines the exit slot width. Ends 108,109 are movable independently of each other and of a flow-contacting face 34E of the divider of deckle member 95. Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications are possible without departing from the scope of the invention defined in the appended claims. Several modifications have been briefly mentioned for purposes of illustration.

Claims: An extrusion apparatus comprising a first flow passageway (14) comprising a manifold (18) and a connecting channel (20) disposed between manifold (18) and an exit orifice (24), a slidably disposed deckle (30, 95) disposed in first flow passageway (14), and a second flow passageway comprising an inlet channel (48) and converging with first flow passageway (14) characterized in that slidably disposed deckle (30, 95) comprises a first plug portion (42) for manifold (18) and a second plug portion (38, 96, 102) for connecting channel (20), that first plug portion (42) extends through an end of the extrusion apparatus into manifold (14) and comprises a channel portion (46, 46D) which is in communication with inlet channel (48), and that second plug portion (38, 96, 102) extends through an end of the extrusion apparatus into connecting channel (20). The extrusion apparatus of claim 1, characterized in that deckle (30, 95) further comprises a divider portion (56, 56D), the second flow passageway further comprises a second channel portion (54, 54D, 54E), and divider portion (56, 56D) comprises a face (34, 34D, 34E) for contacting a first stream in the first flow passageway (14) and a face (62) for contacting a second stream in the second channel portion (54, 54D, 54E). The extrusion apparatus of claims 1 or 2, characterized in that the second plug portion (96, 102) is adjustable to the first plug portion for the manifold (18). The extrusion apparatus of claim 3, characterized in that the second plug portion (96, 102) has an end (101, 108) for defining a width of second channel portion (54D, 54E). The extrusion apparatus of any preceding claim, characterized in that channel portion (46, 46D) is defined by a generally transversely disposed recess in first plug portion (42), and the recess extends exterior to a main body of the extrusion apparatus, and the extrusion apparatus further comprises a stationary member (40) comprising an inwardly projecting portion (66) disposed in precision sliding fit within the recess, and channel portion (46, 46D) is adjustable in extent within the main body of the extrusion apparatus and with respect to stationary member (40), wherein the recess is located in an upper portion of first plug portion (42). A process for coextruding a composite stream comprising passing a first flow stream into a first passageway (14) of an extrusion apparatus into which a slidably disposed deckle (30, 95) extends through an end of the extrusion apparatus, the first passageway comprising a manifold (18) and a connecting channel (20) disposed between the manifold (18) and an exit orifice (24), passing a second flow stream through a second passageway comprising an inlet channel (48) and converging the first flow stream and the second flow stream, characterized in that prior to the converging step the second flow stream is passed through a channel portion (46, 46D) defined by a recess in a first plug portion (42) of the deckle (30, 95) and disposed within the manifold (18), the deckle (30, 95) further comprising a second plug portion (38, 96, 102) for the connecting channel (20) extending through an end of the extrusion apparatus into connecting channel (20). The process of claim 6, characterized in that prior to the converging the second flow stream passes through a second channel portion (54, 54D, 54E), that the deckle (95) further comprises a divider portion (56, 56D) comprising a face (34, 34D, 34E) for contacting the first flow stream and a face (62) for contacting the second flow stream in the second channel portion (54, 54D, 54E). The process of claim 7, characterized in that the second plug portion (96, 102) is adjustable to the first plug portion for the manifold (18), and has an end (101, 108) for defining a width of second channel portion (54D, 54E), and in adjusting the width of the second channel portion (54D, 54E) by adjusting the extent of the second plug portion (96, 102) in the connecting channel (20).

Inventors: CLOEREN PETER F, CLOEREN, PETER F.
Applicants: CLOEREN CO, THE CLOEREN COMPANY
Application year: 1994
Main classification: B29C47
IPC codes: B29C47, B29L7